Well I finally uncovered the old girl and fired her up for the first time this season. She has been sitting since June 2008 with a 1/4 to 1/2 a tank of gas. No Seafoam until the summer of 2009, because I didn`t know about it until then. Probably only put in a couple of ounces then but couldn`t get the engine started with my old wet cell battery, so never got any Seafoam into the carbs that season. So it sat a second winter with gas in the carbs.
Bought a new MF-AGM battery in April 2010, installed it and my *Cosmic Lady* fired up on the second try.
Added about 4 more ounces of Seafoam and started the bike a couple of times that summer. Last fall I turned the petcock off and ran the carbs dry before winter storage to avoid gumming them up. Brought new battery into the house for the winter.
So a week ago I opened the tank cap and the gas is starting to smell a bit rancid. Turned the petcock on, re-installed the battery, put on full choke (temps about 70-75*F) and cranked her over for 10 seconds (timed), stopped to let the starter cool for 30 seconds, then hit the starter again and she fired right up in another 5 seconds.
Woo Hoo another success story for Seafoam!!
So far this thread looks like it should be in the Fuel and Carbs forum.
Now to the point of the title. I clamped my voltmeter probes to the battery terminals prior to starting the engine and was getting just over 12 v.
After starting and on full choke at ~1500 rpm it climbed gradually to just over 13 v.
Idle at 1100 rpm with choke off it dropped 0.2 v to ~12.85 v
2K rpm - 13 V,
then dropped marginally to 12.75 v all the way from 3-5K rpm.
I guess I have some testing to do on the AC voltage stator output, and the r/r to decide which one is weak.